US market "more challenging"
yes, and i think the reason why is the AASLD guidelines, as pointed out by gofish. telbiv gets far mroe favorable endorsement in the canadian guidelines (also pointed out by gofish), and probably the same is unfolding in other ex-US territories
not only was telbiv given the ok as first line in canadian guidelines, it was the only direct acting antiviral NOT mentioned to avoid in HIV coinfected pts not on HAART